1. Field
The following description relates to a frequency efficiency enhancement technology, and more particularly, to a communication technology based on an orbital angular momentum (OAM) mode.
2. Description of Related Art
In modern times, demands for services that transmit and receive a large amount of data such as video, voice, and the like at high speeds have rapidly increased. As a result, in order to increase data capacity of a high-speed point-to-point system in a line-of-sight (LOS) environment, research is being conducted on communication using an orbital angular momentum (OAM) phenomenon. The OAM mode communication is a communication scheme that uses an OAM phenomenon, which is a new physical quantity for distinguishing communication signals using mathematical orthogonality of an OAM mode even when the frequency, polarization, and multi-antenna array characteristics remain the same.
OAM was predicted by Poynting and thereafter introduced in an optical communication field, and thus active research is in progress. In particular, due to a very short wave length, visible light used in optical communication has good straight propagation and high energy concentration characteristics. Accordingly, in an LOS environment, the visible light may be useful in that high-quality lenses and beam splitters are easily manufactured. However, since it is difficult to generate a multi-mode through combination in a frequency band such as micro waves or millimeter waves with relatively long wavelengths, for commercial utilization, there is a need for components for multi-mode transmission.